1. Field of the Invention
This invention relates to a mechanism of a socket wrench wherein the socket wrench is firmly equipped and combined with an inside anvil of a motive tool such as an impact wrench.
2. Description of the Related Art
As a motive tool operated by human power, there is a ratchet handle or an extension bar, and it is generally seen that a combination mechanism between a socket wrench and the motive tool is performed by pushing a hard steel ball into a hollow portion of square hole formed in the socket wrench, while the steel ball is prepared in the anvil of the motive tool by a spring force. Where the socket wrench is small and of light weight, this combination is kept well, but where the wrench is large and of heavy weight, the wrench is eventually easy to be fallen off naturally because of the heavy weight in the due course. Even if the good combination is kept in the beginning, when the combined tool is moved or shaken, the combination is sometimes released. Especially during working time in a narrow place, when this disconnection happens, it results only the socket wrench has fallen off to remains on a bolt-nut side, and it is quite troublesome to find the lost wrench.
With regard to the motive tool of an impact wrench moved by compressed air or electric power, the combination between the socket wrench and the anvil is generally held by utilizing a pin which is penetrating through both the socket wrench and the anvil and by inserting fixedly an O-ring into a ditch formed in circumference of the socket so as to maintain the combination during high speed rotation. In this constitution, however, the O-ring made of rubber is forcibly pressed and spread by centrifugal force or hitting shock caused by the high speed rotation of the socket wrench, and thus it is difficult to maintain the pin.
In order to keep the pin not to be scattered off easily, it is suggested to adopt rubber with high hardness for the O-ring, but if we use this high harness rubber, it becomes very difficult to take the O-ring out of the socket ditch when needed, and also we have to prepare an extra jig so that we may detach smoothly the socket wrench from the motive tool.
On the other hand, it is now marketed to use an E-letter ring made of piano wire in stead of the pin, but when we adopt this E-ring, an extra jig is absolutely required to take of the ring, and also this developed E-ring is sometimes broken off during use by hysteresis imposed by the continual blow caused on the impact wrench.